1202.0397 (C. Lang et al.)

Submillimeter nuclear medical imaging with a Compton Camera using triple
coincidences of collinear β+ annihilation photons and γ-rays    [PDF]

C. Lang, D. Habs, P. G. Thirolf, A. Zoglauer

Modern PET systems reach a spatial resolution of 3-10 mm. A disadvantage of
this technique is the diffusion of the positron before its decay with a typical
range of ca. 1 mm (depending on its energy). This motion and Compton scattering
of the 511 keV photons within the patient limit the performance of PET. We
present a nuclear medical imaging technique, able to reach submillimeter
spatial resolution in 3 dimensions with a reduced activity application compared
to conventional PET. This 'gamma-PET' technique draws on specific positron
sources simultaneously emitting an additional photon with the \beta+ decay.
Exploiting the triple coincidence between the positron annihilation and the
third photon, it is possible to separate the reconstructed 'true' events from
background. In order to test the feasibility of this technique, Monte-Carlo
simulations and image reconstruction has been performed. The spatial resolution
amounts to 0.2 mm (FWHM) in each direction, surpassing the performance of
conventional PET by about an order of magnitude. The simulated detector
geometry exhibits a coincidence detection efficiency of 1.92e-7 per decay.
Starting with only 0.7 MBq of source activity (ca. 200-500 times less compared
to conventional PET) an exposure time of 450 s is sufficient for source
reconstruction.

View original: http://arxiv.org/abs/1202.0397